In 1997, Jeanne Louise Calment of France died at the age of 122, making her the oldest documented human to have ever lived. People who live to be 100 years or older are rare, and only about 1 in 600,000 people in industrialized nations live that long. But is there something genetically unique about centenarians that enables them to age gracefully and relatively disease-free? According to the results of a long-term study at Boston University School of Medicine, the answer is yes.

Jeanne Louise Calment Lived to Age 122:

As part of the New England Centenarian Study, a team of aging research specialists led by Paola Sebastiani and Tom Perls looked at 300,000 genetic markers in 800 centenarians and compared their profiles with those of random individuals. They then developed a genetic model that can compute an individual's predisposition to living a long life and found that centenarians shared a common genetic signature that could predict extreme longevity -- with 77 percent accuracy. The findings represent a breakthrough in understanding how genes influence human life spans.

"Out of 100 centenarians we could correctly predict the outcome of 77 percent, while we incorrectly predicted the outcome of 23 percent," said Sebastiani. The researchers believe the 23 percent error rate can be attributed to genetic variance not yet known and included in the analysis, as well as other factors that influence longevity. "Making healthy lifestyle choices such as eating a well balanced diet or exercising regularly and avoiding exposure to tobacco plays an undisputed role in determining how each of us will age," said Andrew Sugden, international managing editor of Science.